Alarm attachment for door-knobs



(No Model.)

W. P. ALLISON. ALARM ATTACHMENT FOR DOOR KNOBS.

No. 357,887. PaQtentedPeb. 15,1887.

v INVENTOR:

BY" W ATTORNEYS.

-WITNESSES UNITED STATES PATEN OFFICE.

XVILLIAM P. ALLISON, OF KENNEBUNK, MAINE.

ALARM ATTACHMENT FOR DOOR-KNOBS.

SPECIFICATION forming part of Letters Patent No. 357,887, dated February 15, 1887.

(No model.)

To aZZ whom it may concern.-

Be it known that I, WILLIAM P. ALLIsoN, of Kennebunk, York county, State of Maine, have invented new and Improved Alarm Attachments for DoorKnobs, of which the following is a full, clear, and exact description.

My invention relates to an alarm attachment to be applied to door-knob spindles, so that the act of turning the knob for opening the door will sound an alarm; and the invention consists of the special construction of the attachment, as hereinafter described.

Reference is to'be had to the accompanying drawings, forming a part of this specification, in which similar letters of reference indicate corresponding parts in both the figures.

Figure 1 shows infront elevation myinvention applied to the inside of a door, the knobspindle being in section to show clearly the preferred plan of attaching the device to the spindle; and Fig. 2 is a plan view of a doorknob and alarm attachment.

A represents the spindle of a door-lock, to

l which the knobs B B are attached, and which must be turned axially in order to withdraw the bolt O of the lock for opening the door. This motion of the spindle utilize, through suitable mechanism and contrivances, to draw the cord or wire D which represents a simple connection of the device to the striking mechanism of an ordinary door-gong, K, or other alarm. Various means intermediate of the spindle A and cord 1) may be used for com municating the motion of the spindle to the cord; but in order that the whole attachment may be simple and effectual, and may be ap plied to any door and knob, I use two duplicate clamp-plates, D, fitted upon the spindle and held by screws (1, to form two opposite levers, D D", so the alarm will be operated by turning the spindle in either direction. The upper lever, D, is connected by the cord or other connection, E, to the upper end of the lever F, which is centrally pivoted to the plate G upon the pin or stud a. The lower lever, D is connected to the lower end of the lever F by the cord or other connection, E. The

connections E E are by preference held to the lever F by the eccentrics Zrb, pivoted to the lever so as to grasp the connections E E between the eccentrics and the studs 0 a, formed at the ends of the lever F; but other devices for this purpose may be used. The lever Fis connected upon opposite sides of its pivot to the lever H by the plates I I. These plates are slotted, as shown at c e, to receive the screws f f, by which the plates are connected to the lever F, and the opposite ends of the plates are connected by a single rivet to the lever H. The object of the slots e is to permit the spindle to turn in either direction without binding the lever F, and the object of two plates, I, is to cause the lever H to be operated always in the same direction, no matter which way the knobs may be turned.

The lever H, like the lever F, is pivoted to the plate G, and this plate is attached by screws or otherwise to the body J of the door. If desired, the plate G may be omitted, in which case the levers F H will be pivoted directly to the inner surface of the door. By means of the eccentrics b the connections E may be taken up or lengthened to suit the alarm attachment to any door; but in some cases a permanent u nadj ustable connection will be used.

Having thus fully described my invention,

I claim as new and desire to secure by Letters Patent 1. The door-knob spindle provided with levers connected by intermediate mechanism to the lever F, centrally pivoted to asnpport, G, in combination with the lever H, adapted to be connected to the door-bell, and connected to the lever F on opposite sides of its pivot by the slotted plates I, substantially as described.

2. The clamps D, attached to spindle A to form levers D D in combination with the lever F, connections E, lever H, and slotted connections I, connecting the plate F to the plate H, substantially as described.

V. P. ALLISON.

XVitnesses:

Jos. TITCOMB, J OHN MORRIS. 

